Propulsion of ships



Sept. 30, 1930. J 35 MEO 1,777,258

PROPULS ION 0F SHIPS Filed Aug. 20, 1929 2 Sheets-Sheet l Sept. 30, 1930. J. DE MEO PROPULSION OF SHIPS Filed Aug. 20, 1929 2 Sheets-Sheet 2 I Joameo Patented Sept. 30, 1930 JOHN DE MEO, or LoNnoN, ENGLAND raoPoLsroN or srrrrs Application filed August 20, 1929, Serial No.

This invention relates to a system for the propulsion of ships or vessels and is an improvement in or modification of the system claimed in the specification of my prior Patcut No. 239,816.

The system devised according to the above patent embodied means wherebythe.vibration was overcome that was identical to the use of screw propellers andthe usual conventional arrangements of their associated driving mechanism.

Experience has shown that the modern tendenoy of building longer and longer ships and vessels, more particularly liners, results in the use of excessively long propeller shafting and according to my prior patent, an arrangement was described whereby such vibration was prevented or largely minimized, in which the propeller mechanism was disposed centrally and amidship so that any racing of the propeller shaft or shafts due to pitching, was entirely prevented. Such vibration is aggravated by the higher and higher speeds that are adopted.

In connection with the inventors work on the above mentioned prior patent, the following further experience gained by his eX- periments and researches in naval basins and tanks, it has been shown that variations may be made with advantage to further modify and supplement the system embodied in the prior patent according to circumstances arising in connection with any desired design suitably determined for particular services.

Following upon the above observations, the scope of the present invention is to provide suitable and additional installation to the number of propellers needed, say for more than the two or four propellers at the sides of the hull according to the prior patent, by

the provision of additional driving units or propellers arranged in or under the central zone or body of the ship. There will be thus constituted a complementary installation, to

that of the side propellers previously arranged amidship, which can be applied in the case of special limitation in the draft of ships where a difierent distribution of the total horse-power may be required to suit other working conditions in the presence of 387,184, and in Great Britain July 5, 1929.

any variation in the shape of the submerged parts of the hull to house propellers addi tional to the side propellers arranged amidship.

The above additional propellers provided in the midship zone for any particular requirements as to the type of ship or in the case of limitation in the draft, displacement, or speed, will constitute together with the side propellers arranged amidship, as per the previous patent, an installation for the total estimated driving horse-power with the eX- tension or prolongation of the submerged part or underwater body which will form housings for the additional propeller shaft or shafts, such extension being formed by acontinuation of the water line profile with the transverse frame sections of the hull and in the central submerged sections or zones of the centre of gravity of the hull.

Such extensions or prolongations of the lower parts of the hull are harmonized with the architectural lines and shapes appertain ing to the normal practice of naval design as to ensure less frictional resistance arising from the combined shapes of such housings with the transverse frames of the ship, the determination of such shapes or profiles for the particular case or type of ship desired, depending as an embodiment of the design resulting from the tank experiments above referred to, in order that the utmost efficiency will be obtained in the application of the basic principles of the center propulsionsystern referred to in my prior patent.

The. invention will now be described with reference to the accompanying drawings, in

which Figure 1 is a side elevation of a ship as fitted with the improved propulsion system.

Figure 2 is a plan View thereof;

Figure 3 is a plan view of a modified form of Figure 2.

Figure 4 is a modified form of ships hull according to the invention.

Figure 5 is a plan view of the hull according to Figure 4.

Figure 6 is a plan view similar to Figure 5, but modified, and

Figure larged scale, of a ship fitted with the improved propulsion system.

Referring to the examples in Figures 1 and 2, in the side portions of the hull recesses b are provided within which a single propeller c, Figure 1, or two propellers cl, Figure 3, are arranged, the hull forming housings for the accompanying propeller shafts e. Thus far the propelling system is that described in my aforesaid patent, and according to the present invention these arrangements are supplemented by a downward extension or prolongation a in the hull of the vessel at about midway in both directions, transverse and longitudinally, and in addition one or more other propellers f are arranged on, or symmetrically to, the longitudinal axis of the vessel.

In the illustration shown five of such pro pellers are used but the invention is not necessarily confined to this number, any suitable number may be used so long as symmetry is preserved.

Preferably this additional propeller or additional propellers f are arranged at a lower level than the propellers (Z and as shown in Figure 3 for example they are spaced on each side of the centre of the longitudinal axis of the ship when more than one are used.

The associated propeller shafts are use; in such lower part of the extension or prolongation a of the hull and the profile of such extension will be such as will harmonize with the correct architectural lines of the ship and the profile of the extension may be that indicated in Figure 1 where it merges on both iidlels into the usual underwater part of the The forward curve of the extension or prolongation a which is shown in Figure 2 may be modified as indicated in Figure 3, that is to say when two side propellers. (Z are used the forward curve of the extension a will be thatshown in Figure 3 and indicated at g.

eferring to Figure 4, the extension is somewhat prolonged forward of the hull so as to present a gradual change of outline so that it merges into the forward curve at the cut-water of the ship and as indicated in Figure 5 the profile of the extension may be such that it will merge into the general profile or line of the hull as at h when a single side propeller c is used. \Vhen, however, two side propellers are used as shown in Figure 6 then the outline or profile of the extension a will be modified as indicated at In.

From the foregoing description it will be understood that a new propelling system for ships and vessels has been devised according to which there may be used either the centre propeller or propellers only, or the side propeller or propellers only, or they may be used together to constitute a total drive of the horse power desired. The propulsion sys tem is symmetrical and is arranged within the region of the centre of gravity for the displacement of submerged hulls so that no pitching of the vessel can cause vibration of the propeller shafting.

Ail excessive length in the propeller shafts is entirely eliminated and the modified construct-ion of the hull with its under-water extension and prolongation are in harmony with the architectural lines of the ship and fulfil the usual requirements of naval design, the transverse frame structure being suitably modified to take or accommodate the extension of the hull described.

Having now described my invention, what I claim as new and desire to secure by Letters Patent is V 1. In combination with a ship having the sides of its hull provided with symmetrically disposed recesses, propellers operable in the recesses, said hull having a prolongation extending downwardly in the central zone of the ship, shafts supported by such prolongation and having propellers. carried thereby for combined operation with the propellers in the recesses.

2. In combination with a ship having the sides of its hull provided in the region amidship with symmetrically disposed recesses, propeller shafts extending into the recesses and having propellers fixed thereon for oporation in said recesses, the keel of the hull having a prolongation extending longitudinally thereof and having its aft end extending between the recesses, and propeller shafts extending rearwardly from the prolongation, propellers fixed on said shafts for combined operation in the central zone of the ship around the amidship section.

3. In combination with a ship having the sides of its hull provided in the region amidship with symmetrically disposed inwardly extending recesses, propeller shafts extending from the hull into the recesses and having propellers fixed thereto, a prolongation extending longitudinally of the ships keel and depending from the center region about the amidship section, propeller shafts. eie tending from the rear end of the prolongation and in a plane below the first named propeller shafts, and propellers l'xed to the latter shafts for combined operation in the center zone corresponding to the recesses.

In testimony whereof I have signed my name to this specification.

JOHN DE MEO. 

